This invention relates to modular sprinkler devices and, more specifically, the invention relates to an improved sprinkler which incorporates a spray plate mounted for wobbling/rotating motion referred to herein as "nutation".
Moving irrigation systems, such as conventional pivot move (or center pivot) and lateral (or linear) move systems, are known to incorporate conduit truss span assemblies which mount sprinkler heads, spaced along the truss assemblies for sprinkling or irrigating relatively large areas of land. The sprinkling heads may be mounted on top of the truss assemblies in a normal upright position, or they may be inverted and suspended from the span assemblies by means of drop tubes. The sprinkler heads typically incorporate rotatable stream distributors (also referred to as rotor plates or spray plates), fixed spray plates or bubbler devices.
When irrigating large areas of land with center pivot or linear systems, the sprinklers need to be spaced apart as tar as possible to minimize system hardware costs. To obtain an even distribution of the water at wide spacings requires sprinklers that simultaneously throw the water long distances and produce sprinkling patterns that are very even when overlapped with adjacent sprinklers. These two requirements are somewhat exclusive in that maximum radius of throw is achieved with concentrated streams of water shooting at a relatively high trajectory angle (approximately 20.degree. up from horizontal); however, these streams tend to produce a "donut" shaped sprinkling pattern that does not overlap evenly.
It is the principal objective of this invention to solve the above problem by employing a multi-stream rotor or spray plate that wobbles as it rotates. Additionally, the rotor or spray plate is confined to move in a set motion through the use of a conical gear arrangement on the rotor or spray plate, and a mating gear arrangement on the stationary sprinkler cap assembly. This arrangement results in a controlled nutating movement of the spray plate which causes the water streams to rotate consistently and fill in the sprinkling pattern uniformly.
In an exemplary embodiment of the invention, the sprinkler itself includes generally a sprinkler body, a removable cap assembly, a nozzle and a connector/adaptor. The cap assembly is modified to incorporate a rotor or spray plate which redirects a stream issuing from the fixed nozzle in a substantially radial direction by reason of a multi-groove configuration on a plate. These grooves are provided with combined radial and circumferential shape components (as opposed to only a radial component) so that the spray plate would otherwise be caused to rotate when struck by the stream emitted from the nozzle. In addition, the underside of the rotor or spray plate includes a central annular hub projecting from the underside of the plate. A shaft supports the spray plate at one end thereof and projects outwardly from the hub. The other end of the shaft receives a spherical ball which may be press fit or otherwise secured onto the shaft. The ball, in turn, is received within a complementary spherical ball retainer cage secured to the cap assembly. This universal type mounting arrangement permits universal wobbling movement of the shaft about an axis extending through the nozzle and the center of the cap assembly as the ball moves within the cage. The periphery of the underside of the spray plate is formed with a plurality of gear teeth which are designed to mesh with a plurality of gear teeth provided on the interior surface of the otherwise stationary cap assembly. In the preferred embodiment, sixteen gear teeth are provided on the cap assembly and fifteen gear teeth are provided on the underside of the spray plate.
The arrangement is such that the wobbling action causes the center of the rotor or spray plate to orbit in one direction of rotation about the aforementioned axis, and because of the wobbling action, it will be appreciated that the gear teeth on the rotor or spray plate will partially and progressively engage the gear teeth on the stationary cap assembly in that same direction. In other words, as the water stream from the nozzle travels through the grooves in the spray plate, it causes the rotor or spray plate to nutate about the ball center. As the center of the rotor or spray plate wobbles in, for example, a counter-clockwise direction of rotation, the perimeter of the rotor or spray plate is caused by the unequal number of gear teeth to advance stepwise (by one gear tooth per revolution) in a clockwise direction of rotation. This action will be described in greater detail hereinbelow. By so controlling the nutating movement of the spray plate, uncontrolled spinning of the plate is prevented and a uniformly even sprinkling pattern is achieved. To further enhance the ability of the sprinkler to provide a uniform sprinkling pattern, the groove configurations in the spray plate may be formed with varying surface trajectories and groove widths, shapes, etc.
Thus, in accordance with the broader aspects of the invention, there is provided a sprinkler body comprising a body portion having an inlet at one end and an outlet at an opposite end; a nozzle secured in the outlet; a cap assembly secured to the body and supporting a rotatable spinner plate located downstream of the outlet, the spinner plate having a plurality of stream distributing grooves formed on one side thereof configured to cause the spinner plate to rotate when struck by a stream emitted from the nozzle; the improvement comprising a universal joint for supporting the spinner plate in the cap assembly such that the spinner plate is caused to wobble as it rotates, and respective sets of gear teeth on the cap assembly and the spinner plate arranged for progressive partial engagement in the one direction, and wherein the respective sets of gear teeth are configured to cause the spray plate to advance relative to the cap assembly in an opposite direction of rotation.
In another aspect, the present invention relates to a sprinkler comprising a sprinkler body having an inlet end and an outlet end, the outlet end having a stream emitting orifice; a rotor plate mounted to a support downstream of the orifice, the rotor plate having a plurality of substantially radial grooves formed in one side of the plate, arranged to cause rotation of the plate when struck by a stream emitted from the orifice, the rotor plate having a shaft extending out of and away from an opposite side of the plate, a free end of the shaft having a ball element secured thereto, the ball element received in a ball retaining cage on the support.
It will be appreciated that the controlled rotating/wobbling motion results in water being thrown from the rotor plate at different trajectory angles in a continuously changing manner, the motion controlled by the use of progressively partially meshing gear teeth to thereby cause the water streams to rotate consistently while filling in the sprinkling pattern evenly, thus avoiding the "donut" pattern described hereinabove.
Other objectives and advantages of the present invention will become apparent from the detailed description which follows.